JP2011086426A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide at a low cost a plasma display panel which uses a low-cost phosphor material suppressing deterioration of luminance and luminous efficiency and maintains image display quality by preventing deterioration of luminance. <P>SOLUTION: The plasma display panel has a plurality of discharge cells of one color or a plurality of colors arranged and phosphor layers of a color corresponding to the discharge cells. The phosphor layers emit light by being excited by ultraviolet rays, and at least one phosphor layer out of the phosphor layers has a composition: (Y, Gd)<SB>0.95</SB>BO<SB>3</SB>:Eu<SB>0.05</SB>, and its average particle size is 0.8-1.3 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plasma display panel used for image display such as a television, and more particularly to a configuration of a phosphor layer that emits light when excited by ultraviolet rays.

  Plasma display panels (hereinafter referred to as PDPs) can achieve higher definition and larger screens, so full-spec high-definition televisions and large-sized public display devices in the 50-inch class to over 100-inch class are also available. Commercialization is progressing.

  The PDP is composed of a front plate and a back plate. The front plate is a glass substrate made of sodium borosilicate glass by a float method, a display electrode composed of a striped transparent electrode and a metal bus electrode formed on one main surface, and the display electrode A dielectric layer that covers and acts as a capacitor, and a protective layer made of magnesium oxide (MgO) formed on the dielectric layer are provided.

  On the other hand, the back plate has a glass substrate provided with pores for enclosing (also referred to as introducing) exhaust gas and discharge gas, and stripe-shaped address electrodes (also referred to as data electrodes) formed on one main surface thereof. And a base dielectric layer that covers the address electrodes, a partition formed on the base dielectric layer, and a phosphor layer that is formed between the partitions and emits red, green, and blue light.

  The front plate and the back plate face each other on the electrode formation surface side, and the periphery thereof is sealed with a sealing material, and a mixed gas of Ne—Xe is predetermined as a discharge gas in the discharge space partitioned by the partition walls. It is sealed with the pressure of

  The PDP discharges a discharge gas by selectively applying a video signal voltage to a display electrode, and ultraviolet rays generated by the discharge excite each color phosphor layer to emit red, green, and blue light, thereby producing a color image. Display is realized.

  The PDP performs full color display by additively mixing so-called three primary colors (red, green, and blue). In order to perform this full-color display, the PDP is provided with a phosphor layer that emits light of each of the three primary colors, red (R), green (G), and blue (B), and the phosphor constituting the phosphor layer. The particles are excited by ultraviolet rays emitted in a PDP discharge cell to generate visible light of each color (see Patent Document 1).

Examples of the phosphors of the respective colors include (Y, Gd) BO ₃ : Eu ³⁺ , Y ₂ O ₂ S: Eu ³⁺ that emits red, and (Ba, Sr, Mg) O · aAl ₂ that emits green. O ₃ : Mn ²⁺ , Zn ₂ SiO ₄ : Mn ²⁺ , and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ that emits blue light are known.

JP 2003-131580 A

  In recent years, cost reduction in PDPs has become an important issue due to market demands, and it is necessary to realize low cost also in the phosphor that is a constituent element.

  As a means for reducing the cost of the phosphor material, it is possible to reduce the amount of rare earth metal used, whose price has continued to rise due to a decrease in production. This reduces the amount of expensive raw material used in the phosphor, and can be expected to greatly reduce the cost.

  However, rare earth metals are often used as the emission center of phosphors, and reducing rare earth metals reduces the number of atoms involved in light emission in the phosphor material. Leading to a decrease in luminous efficiency.

In particular, in the case of red phosphor (Y, Gd) BO ₃ : Eu ³⁺ , changing the addition amount of Gd, which is also a rare earth metal element, leads to a decrease in luminance and light emission efficiency because the composition of the crystal shifts. .

Therefore, the present invention aims to reduce the cost of phosphor materials by suppressing the decrease in luminance and light emission efficiency in the red phosphor (Y, Gd) BO ₃ : Eu ³⁺ and reducing the amount of rare earth metal used. And As a result, it is possible to prevent a decrease in luminance due to a decrease in the emission center activation amount and to provide a PDP capable of displaying a good image at a low cost.

In order to achieve the above object, the PDP according to the present invention includes a plurality of discharge cells of one color or a plurality of colors, and a phosphor layer of a color corresponding to the discharge cell is disposed. A PDP that emits light when excited by ultraviolet rays, wherein at least one of the phosphor layers has a composition formula of (Y, Gd) _0.95 BO ₃ : Eu _0.05 and has an average particle size of It is 0.8-1.3 micrometers. Here, at least one of the phosphor layers has a composition formula of (Y, Gd) _0.95 BO ₃ : Eu _0.05 and a specific surface area of 3.0 to 3.5 m ² / g. It is desirable to be.

  According to the present invention, it is possible to realize a low-cost phosphor material that suppresses a decrease in luminance and light emission efficiency, and it is possible to provide a PDP that maintains image display quality at low cost.

Plan view showing schematic configuration of electrode arrangement of PDP Partial cross-sectional perspective view showing schematic configuration in image display area of PDP

  Hereinafter, a PDP according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing a schematic configuration of an electrode arrangement of a PDP. The PDP 100 includes a front glass substrate (not shown), a rear glass substrate 102, a sustain electrode 103, a scan electrode 104, an address electrode 107, and an airtight seal layer 121. N sustain electrodes 103 and scan electrodes 104 are arranged in parallel. M address electrodes 107 are arranged in parallel. The sustain electrode 103, the scan electrode 104, and the address electrode 107 have an electrode matrix having a three-electrode structure, and a discharge cell is formed at the intersection of the scan electrode 104 and the address electrode 107.

  FIG. 2 is a partial cross-sectional perspective view showing a schematic configuration in the image display area of the PDP. The PDP 100 includes a front panel 130 and a back panel 140. A sustain electrode 103, a scan electrode 104, a dielectric glass layer 105, and an MgO protective layer 106 are formed on the front glass substrate 101 of the front panel 130. On the rear glass substrate 102 of the rear panel 140, address electrodes 107, a base dielectric glass layer 108, barrier ribs 109, and phosphor layers 110R, 110G, and 110B are formed.

  The front panel 130 and the back panel 140 are bonded together, and a discharge gas is sealed in a discharge space 122 formed between the front panel 130 and the back panel 140, thereby completing the PDP 100.

  Next, a method for manufacturing the PDP 100 will be described with reference to FIGS. First, a method for manufacturing the front panel 130 will be described. On the front glass substrate 101, N sustain electrodes 103 and scan electrodes 104 are formed in stripes. Thereafter, sustain electrode 103 and scan electrode 104 are coated with dielectric glass layer 105. Further, an MgO protective layer 106 is formed on the surface of the dielectric glass layer 105.

The sustain electrode 103 and the scan electrode 104 are formed by applying a silver paste for an electrode containing silver as a main component by screen printing, followed by baking. The dielectric glass layer 105 is formed by applying a paste containing a bismuth oxide glass material by screen printing and then baking. The paste containing the glass material is, for example, 30 wt% bismuth oxide (Bi ₂ O ₃ ), 28 wt% zinc oxide (ZnO), 23 wt% boron oxide (B ₂ O ₃ ), and 2.4 wt%. % Silicon oxide (SiO ₂ ) and 2.6% by weight aluminum oxide. Further, it is formed by mixing 10% by weight of calcium oxide (CaO), 4% by weight of tungsten oxide (WO ₃ ) and an organic binder (a solution of 10% ethyl cellulose in α-terpineol). Here, the organic binder is obtained by dissolving a resin in an organic solvent. In addition to ethyl cellulose, an acrylic resin can be used as the resin, and butyl carbitol can be used as the organic solvent. Furthermore, you may mix a dispersing agent (for example, glyceryl trioleate) in such an organic binder.

  The coating thickness of the dielectric glass layer 105 is adjusted so as to have a predetermined thickness (about 40 μm). The MgO protective layer 106 is made of magnesium oxide (MgO), and is formed to have a predetermined thickness (about 0.5 μm) by, for example, a sputtering method or an ion plating method.

  Next, a method for manufacturing the back panel 140 will be described. On the back glass substrate 102, silver paste for electrodes is screen-printed and baked to form M address electrodes 107 in stripes. A paste containing a bismuth oxide glass material is applied on the address electrode 107 by a screen printing method and then baked to form a base dielectric glass layer 108. Similarly, a paste containing a glass material based on bismuth oxide is repeatedly applied at a predetermined pitch by a screen printing method and then baked to form partition walls 109. The discharge space 122 is partitioned by the barrier ribs 109 to form discharge cells. The distance between the barrier ribs 109 is set to about 130 μm to 240 μm in accordance with a full HD television of 42 inches to 50 inches and an HD television.

A red phosphor layer 110R, a green phosphor layer 110G, and a blue phosphor layer 110B are formed in a groove between two adjacent barrier ribs 109. The red phosphor layer 110R is made of, for example, a (Y, Gd) BO ₃ : Eu red phosphor material. The blue phosphor layer 110B is made of, for example, a blue phosphor material of BaMgAl ₁₀ O ₁₇ : Eu. The green phosphor layer 110G is made of, for example, a Zn ₂ SiO ₄ : Mn green phosphor material.

  The front panel 130 and the back panel 140 manufactured in this way are overlapped facing each other so that the scanning electrode 104 of the front panel 130 and the address electrode 107 of the back panel 140 intersect. Sealing glass is applied to the periphery and baked at about 450 ° C. for 10 minutes to 20 minutes. As shown in FIG. 1, the front panel 130 and the back panel 140 are sealed by forming an airtight seal layer 121. Then, once the discharge space 122 is evacuated to a high vacuum, a discharge gas (for example, helium-xenon-based or neon-xenon-based inert gas) is sealed at a predetermined pressure to complete the PDP 100.

  Next, a method for manufacturing each color phosphor material will be described. In the following description, a phosphor material manufactured by a solid phase reaction method is used.

BaMgAl ₁₀ O ₁₇ : Eu, which is a blue phosphor material, is produced by the following method. Barium carbonate (BaCO ₃ ), magnesium carbonate (MgCO ₃ ), aluminum oxide, and europium oxide (Eu ₂ O ₃ ) are mixed so as to match the phosphor composition. The mixture is fired at 800 ° C. to 1200 ° C. in air, and further fired at 1200 ° C. to 1400 ° C. in a mixed gas atmosphere containing hydrogen and nitrogen.

The green phosphor material is produced by the following method. Zn ₂ SiO ₄ : Mn used as the green phosphor material in the embodiment of the present invention is the ratio of the Zn element and the Mn element to the Mn element at the particle surface of 10 nm or less, that is, (Mn / (Zn + Mn) ) Is 0.05 to 0.08, and the ratio of Si element to the sum of Zn element and Mn element, that is, ((Zn + Mn) / Si) is 1.97 to 2.02. Yes.

Here, Mn / (Zn + Mn) and (Zn + Mn) / Si at a particle surface of 10 nm or less of Zn ₂ SiO ₄ : Mn can be measured with an XPS apparatus. XPS is an abbreviation for X-ray Photoelectron Spectroscopy, which is called X-ray photoelectron spectroscopy, and is a method for examining the state of elements up to 10 nm near the surface of a substance. Mn / (Zn + Mn) and (Zn + Mn) / Si are values calculated by analyzing each of Zn, Si, and Mn using an XPS apparatus.

Next, the red phosphor in the embodiment of the present invention will be described. The red phosphor in the embodiment of the present invention is (Y, Gd) BO ₃ : Eu ³⁺ , but when it is intended to reduce the cost, it is generally possible to reduce the Eu addition concentration. However, as described above, this conventional method has a problem that the luminance is lowered.

Accordingly, the inventors have conducted various studies to set (Y, Gd) _0.95 BO ₃ : Eu _0.05 as a red phosphor material, an average particle diameter of 0.8 to 1.3 μm, and a specific surface area of 3.0 to 3.5 m. It has been found that when used as ² / g, it is possible to prevent a decrease in luminance of the PDP. This is because when the average particle size of the phosphor material is larger than 1.3 μm, the phosphor of the phosphor layer is not dense and the luminance is lowered, and when the average particle size is smaller than 0.8 μm, This is probably because the body particles become too small, and the luminance similarly decreases.

The same can be said for the specific surface area. When the specific surface area is larger than 3.5 m ² / g, the phosphor of the phosphor layer is not dense and the luminance is lowered, and the specific surface area is 3.0 m. ^When it is less than ² / g, the phosphor particles become too small, and the luminance similarly decreases.

  In the embodiment of the present invention, the definition of the average particle size and the specific surface area is used in order to achieve both cost and luminance from the above points.

  The inventors consider that this is caused by using the above-described red phosphor to form a phosphor layer having a thick sidewall. By using the phosphor material in the embodiment of the present invention, when the discharge cell is viewed from directly above, a large number of phosphor layers applied to the barrier ribs are stacked, and the phosphor layer is relatively thick in the vicinity of the upper portion of the barrier ribs. As a result, the optical path of visible light reaching the discharge cell opening region is shorter than in the prior art, so that the influence of diffusion and absorption by other components of the PDP is reduced, and the luminance is increased. As a result, even if the amount of Eu activation, which is a rare earth metal element, is reduced, the luminance and luminous efficiency can be maintained.

A manufacturing method of (Y, Gd) _0.95 BO ₃ : Eu _0.05 which is a red phosphor material is as follows. First, the conditions for producing a normal red phosphor material include yttria compounds such as yttria oxide (Y ₂ O ₃ ), gadolinium oxide compounds (Gd ₂ O ₃ ), boric acid (H ₃ BO ₃ ), and europium oxide as raw materials. (EuO ₂ ) is prepared, and each of these raw materials is weighed and collected according to the composition formula described above, and sufficiently mixed by a dry method.

Subsequently, the mixture is filled in a heat-resistant container such as “crucible” made of alumina, carbon, or platinum, and pre-baked at a temperature of 600 ° C. to 800 ° C. Then, the main calcination is performed at a temperature of 1100 ° C. to 1300 ° C. in a mixed gas atmosphere containing oxygen and nitrogen, and the obtained baked product is crushed, washed, dried, and sieved (Y Gd) A phosphor material with _0.95 BO ₃ : Eu _0.05 is obtained. In the present invention, in order to produce particles smaller than usual, the raw materials were small particles having a particle size of 1 μm or less, and the firing time was further shortened to 1 to 2 hours.

  As described above, according to the present invention, a low-cost phosphor material that suppresses a decrease in luminance and light emission efficiency can be realized, and it is industrially useful in that a PDP maintaining image display quality can be provided at a low cost. is there.

100 PDP
DESCRIPTION OF SYMBOLS 101 Front glass substrate 102 Back glass substrate 103 Sustain electrode 104 Scan electrode 105 Dielectric glass layer 106 MgO protective layer 107 Address electrode 108 Base dielectric glass layer 109 Partition 110R Phosphor layer (red phosphor layer)
110G phosphor layer (green phosphor layer)
110B phosphor layer (blue phosphor layer)
121 airtight seal layer 122 discharge space 130 front panel 140 back panel

Claims (2)

A plasma display panel in which a plurality of discharge cells of one color or a plurality of colors are arranged, a phosphor layer of a color corresponding to the discharge cell is disposed, and the phosphor layer is excited by ultraviolet rays to emit light, At least one of the phosphor layers has a composition formula of (Y, Gd) _0.95 BO ₃ : Eu _0.05 and an average particle diameter of 0.8 to 1.3 μm. Plasma display panel. At least one of the phosphor layers has a composition formula of (Y, Gd) _0.95 BO ₃ : Eu _0.05 and a specific surface area of 3.0 to 3.5 m ² / g. The plasma display panel according to claim 1.

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